Re: 4 the Faq: Strengths and Weaknesses of Data Models

"Costin Cozianu" <c_cozianu_at_hotmail.com> wrote in message news:2t5n2uF1sgejuU1_at_uni-berlin.de...
> Kenneth Downs wrote:
>
> > It seems to be taken for granted by the majority in this ng that the RDM
is
> > superior to the hierarchical and network data models. I am in that
> > majority, but I realize it is probably for me more a matter of faith
than
> > proof.
> >
> > So the question is: why did RDM win the database wars? Was it really on
> > strengths, or was it, shudder to think, just one of those trends that IT
> > goes through?
> >
> > What is normally stated in the group is that RDM has a mathematical
basis
> > that gives us a strategy for correctness, which Hierarchical and Network
> > did not. Yet somebody in this ng mentioned a few days ago that those
> > models were given a more rigorous footing later on. Could the
hierarchical
> > model now be just as thorough, except that RDM already won?
> >
>
> The fact that something has a mathematical basis or a mathematical
> formalism, says nothing about the value and the adequacy.

agreed.

> Let me tell you a secret: everything that fits inside a computer is a
> mathematical object. And regardless of uninformed claims to the contrary
> , you can have a mathematical model behind everything: OO, relational
> model, SQL, IMS, Cobol, X86 machine code, XML -- any programming concept
> of all.As a matter of fact there are lots of mathematical models, even
> several alternative for the same target.

Yes. If you think of a mathematical model like other models, as a metaphor, you can map many different mathematical metaphors to the same object.

> The greatest problem though is how adequate is some mathematical model
> for the chief purpose in programming practice : managing complexity and
> achieving correctness.

or for solving business problems; assisting people in getting their jobs done, ...

> Most mathematical models are complicated,
> complex, unintuitive, not easy to make derivations with, ugly (as per
> Dijkstra: *beauty is our business* ) and suffers quite a lot of
> undesirable properties as mathematical models nevertheless.
>
> Looking from this point of view, the classical relational model it is a
> piece of jewelry.

I'll accept it as a gem, but I think we have exaggerated its usefulness and have failed to make significant progress in the database arena for the past couple of decades in part because of the restrictions of the model and in part because of the implementations of the model. --dawn

>
> Costin
Received on Sat Oct 16 2004 - 22:21:14 CEST